Internally pressurized package with heat-sealable closure member

摘要

A pressure-tight packaging, intended particularly for tennis balls, has an opening (3) which is adapted to be sealed by a closure member (4) upon pressurizing the container. Closure member (4) is of substantially planar configuration and is made of a plastics material, which is first warmed by the pressurizing gas on filling the container and is then forced into abutment with the container wall by the gas pressure so as to become welded or glued to the container wall and thus to seal the opening (3).